Presser foot mechanism for shoe sewing machines



June 15, 1943. 0, s 2,321,596

PRESSER FOOT MECHANISMS FOR SHOE SEWING MACHINES Filed NOV. 14, 1941 5 Sheets-Sheet l June 15, 1943.

PRESSER FOOT MECHANISMS FOR SHOE SEWING MACHINES 3 Sheets-Sheet 2 O. R. 'HAAS Filed Nov. 14, 1941 June 15, 1943. O. R. HAAS 2,321,596

PRESSEIR FOOT MECHANISMS FOR snos SEWING mcnnms Filed Nov. 14, 1941 I s Sheets-Sheet 3 [I ll Wiirwss jonzon #&%vm I I Patented June 15, 1943 um'rso srarss PATENT orrics PRESS'ER F001 MECHANISM FOR SHOE S-ElVIN G MACHINES Otto R. Haas, North Beverly, Mass, assignor to United Shoe Machinery Corporation, Fleming ton, N. J a corporation of New Jersey Application November 14, 1941, Serial N 0. 419,072

15 Claims.

The present invention relates to shoe sewing machines and more particularly to improvements in presser foot actuating mechanisms for wax thread machines of the type designed for connecting the Wei-ted upper and outsole of a Goodyear welt shoe with a-lockstitch seam. Machines of this type are disclosed in U. S. Letters Patent of Ashworth No. 1,169,999, of February 1,

1916, and in an application for patent of the present inventor, Serial No. 294,926, filed Septemper 14, 1.939.

In sewing together the welted upper and outsole of a Goodyear welt shoe, the resistance of the materials in the work'operated upon to penetration and operation of the stitch forming devices necessitates a relatively heavy clamping pressure to secure them in place. This pressure is relieved during each sewing cycle to enable the materials -to 'be fed a stitch length and again applied first yieldingl-y with .a light pressure and then with a renewed heavy pressure during the succeeding stitch forming cycle. the type above referred 'to'are heavily constructed and when operated at high speeds, according to present day-sewing practices, are frequently subject to extreme wear from vibration and similar causes.

In the machines of the patent and application referred to, a mechanical presser loot actuating mechanism having either a frictional or pawl and ratchet lock is employed to hold the clamping pressure on the work during stitch formation. This lock is extremely efiicient when properly adjusted but under certain circumstances, after excessive wear and accumulation of foreign matter along its frictional surfaces, becomes noisy and ineiiective for the purposes intended when operated at high speeds, thus rendering the entire mechanism incapable of securing the work properly in relation to the stitch forming and work feeding devices. As a result, the spacing between stitches inserted by the machine becomes variable and diificulty is encountered by the operator in guiding the work to form an acceptable seam.

An important object of the present invention is to provide a presser foot actuating mechanism for a shoe sewing machine of the type referred to which is not subject to the limitations affecting the-usual mechanisms having a mechanical p-ress'er foot lock and which may be operated entirely by hydraulically driven connections. Other objects are to provide a presser foot mechanism in which a light yielding application of clamping pressur in the mechanism Machines of is not subject to mechanical limitations encountered in the use of springs and heavy linkages but in which the clamping pressure may be applied positively with either a light .or relatively heavy force, according to the manner of adjustment for the type of work operated upon. Further objects are to simplify and improve the operation of a shoe sewing machine in which the work is secured in operating position by pressure applied between a work support and a presser foot and relieved during each sewing cycle to en able the work to be fed.

With these andother objects in view, the present invention relates to the provision in a shoe sewing machine having a presser foot and a work support for clamping and releasing the work, of presser foot actuating mechanism comprising a liquid pressure responsive member connected to the foot and hydraulic pressure means forapplying the pressure to and relieving the pressure from the responsive member during each sewing cycle. By the use of a hydraulic actuating mechanism, vibrations set up in the mechanical connections between the presser foot and the 5 pressure responsive member are absorbed in large degree by liquid acting'on the pressure responsive member, thus causing movements imparted to the presser foot actuating mechanism to be transferred accurately to the presser foot With-- out variation from one sewing cycle to another, particularly at high speeds. Also, the connections between the presser foot and the pressure responsive member are subject to less strain and wear than the connections of the usual mechanical presser foot mechanism.

Preferably, according "to this feature of the invention, the hydraulic pressure means includes a continuously driven pump and a valve actuated during each sewing cycle to control the passage of liquid from the pump to the pressure responsive member, In order to provide liquid momentarily in greater volume than furnished by the pump so that even during high speed operation of the present machine, an adequate pressure will be maintained, a pressure storage chamber isconnected between the pump and the control valve. As hereinafter described, a metering device also is connected between the source of pressure and the pressure responsive member to limit the movement of the presser foot to an extent sufficient for releasing and clamping the work securely. In one form of this metering device, a cylinder provided. with a piston slidably mounted therein is suitably connected in the by draulic system to block the flow-of liquid after" a predetermined movement of the presser foot by the pressure responsive member. In certain of the broader aspects of this feature, the invention may be employed to advantage with any fluid capable of being compressed and controlled accurately with a metering device, regardless of whether the fluid is expansiole or incompressible.

As in most modern sewing machines, the machine in which the features of the present invention are embodied is provided with driving and stopping mechanisms for bringing the sewing shaft to rest with the stitch forming devices in predetermined relative positions. In the present form of a further feature of the invention, a by-pass value actuated by the driving and stopping mechanisms is provided with suitable ports and properly connected to the hydraulic system to cause the work clamping pressure on the responsive member to be relieved and the work released whenever the sewing shaft is brought to rest.

Other features of the invention consist in the devices, combinations and arrangements of parts hereinafter described and claimed which, together with the advantages to be obtained thereby, will be readily understood by those skilled in the art from the following description taken in connection with the accompanying drawings, in

which Fig. 1 is a view in side elevation of so much of an outsole shoe sewing machine as is necessary to illustrate a construction embodying the present features of the invention; Fig. 2 is a vertical sectional view, on an enlarged scale, of a stopping by-pass valve illustrated in Fig. 1; Fig. 3 is a vertical sectional view on an enlarged scale of a construction including a main control valve, the by-pass valve, and a metering device, all shown in Fig. 1; Fig. 4 is a horizontal sectional view of the metering device illustrated in Fig. 3; Fig. 5 is a horizontal sectional view of the bypass valve; Fig. 6 is a view in front elevation of the by-pass valve base illustrating the passages leading to the various openings therein; and Fig. '7 is a diagrammatic view of the passages and connections in the hydraulic portions of the presser foot actuating mechanism, including fiat developments of the outer surfaces on the main control valve and the stopping by-pass valve.

The illustrated machine is of the same construction and mode of operation, except as hereinafter described, as those machines disclosed in the patent and application above referred to and is provided with a curved hook needle 2 and a curved awl 4 acting together with other stitch forming devices to insert a locksti-tch seam in thick heavy materials such as the welt and outsole of a leather shoe. In operation, the work is first penetrated by the awl, after which the awl retracts, followed by the needle until the hooked end of the needle is in position to receive a loop of thread. The threaded needle then retracts and the loop of thread is carried about a supply of locking thread by a shuttle indicated at 6. After the awl penetrates the work, it moves in the direction of feed a stitch length to bring the perforation formed by the awl into line with the needle. During the passage of the needle through the work, the work is held clamped between a work support 8 secured to the frame of the machine and a presser foot Ii! fulcrumed on a fixed shaft l2. The stitch forming devices are actuated by either one of a pair of sewing shafts M andiii provided with suitable cams and cranks to impart the proper movements to the stitch forming devices. The sewing shafts are geared to rotate together in opposite directions and are driven through driving and stopping mechanisms constructed and arranged as in U. S. Letters Patent to Ashworth No. 1,233,539, of July 17, 1917.

In the machines of the patents and application, a cam on a shaft corresponding to the sewing shaft [4 acts on a cam lever comprising a mechanical actuating mechanism connected to the presser foot to impart the proper work clamping and releasing movements thereto to cause the work to be clamped with a uniform pressure. In the machines of the patents, an additional action of the cam enables the work to be released by movement of the presser foot away from the surface of the work through a uniform distance during each sewing cycle. The presser foot actuating mechanism in both the patents and application is connected with a spring acting after the work is released to bring the presser foot yieldingly against the surface of the work. After the presser foot is brought again the surface of the work, the cam on the sewing shaft causes the work to be compressed and the position of the presser foot to remain stationary until the next feeding movement of the work occurs.

To hold the presser foot stationary in the machine of the patents, the mechanism is locked by a friction controlled locking device in the form of a threaded rod and nut, the positions of which are maintained by preventing rotation of the nut on the threaded rod during the proper portions of each sewing cycle. The nut of the locking device in Patent No. 1,169,909 is gripped frictionally to hold it from rotation by a springpressed lever which isactuated to release the nut through connections to a cam lever, the motion of which is in excess of that needed to cause the gripping lever to engage the nut. Thus, when the machine is running at a high speed, the grip-- ping action of the lever on the nut occurs during movement of'the cam lever and as a result;

if the parts become worn, undesirable impacts and irregularities in locking action of the presser foot mechanisms may occur between the cam lever and the nut as a consequence of vibration in the connecting parts.

The presser foot actuating mechanism of the application consists of a pair of ratchet arms, one of which is rigidly connected to the presser foot and the other yieldingly connected. The

rigid ratchet arm is engaged by a locking pawl on a fixed pivot and the yielding ratchet arm by a cam actuated pawl to cause the presser foot to clamp the work intermittently during sewing.

The diificulty with the use of pawls is in the uncertainty with which they engage the teeth of their ratchets and the consequent irregularity of clamping and locking action on the presser foot.

To avoid vibration in the presserfoot actuating mechanism of a shoe sewing machine and to enable a presser foot to be moved with precision through its work clamping and releasing cycle.

regardless of the speed of sewing, a feature of the present invention relates to the use of a wholly hydraulic presser foot actuating mechanism, the presser foot being actuated entirely by a presser responsive member without the use of springs or other motion retarding or impact producing devices. As illustrated in Fig. l of the drawings, the presser foot IE1 has an. arm i8 connected bya link 20 to a lever 22 fulcrumed on a stud 26 rigid in the machine frame. The lever 22 is directly connected to the pressure responsive member by a link 26. The only other the opening 52 with which the tube 58 is connected. The port II8 also discharges radially through the cavity I88 of the main valve body.

The main valve body I8 has an internal perforated hub, with a central opening in which is keyed the lower end of a vertical valve shaft H2 passing through the flanged bearing I89 and a bearing I I3 on the machine frame. Above the bearing H3 is a helical gear Il4 meshing with an idler gear H5 rotating on a horizontal stub shaft H6 in the machine frame. The idler gear in turn meshes with a gear II8 secured to the sewing shaft I6, the valve shaft being driven thereby at the same speed of rotation with the exhaust port I84. Resulting pressure in the opening 52 causes oil to flow through the passages 84, 5|, the tube 58 and the lower end of the actuating cylinder 38. Oil pressure on the lower end of th piston 36 causes the presser foot to clamp the work and the exhaust connection through port I84, opening I88, passages I88, 41, and tube 46 enables oil to flow as required from the upper end of the actuating cylinder. Continued rotation of the valve body again covers the openings 52 and I86 and causes ports 88 and I I8 to uncover the openings 88 and 52, respectively, in the valve housing. Pressure through port 86 then forces oil through opening 88, passage 98 into the metering cylinder 82. As the oil moves into the cylinder 92, the piston 84 is carried away from the stop screw 96 towards the forward end of the cylinder displacing oil in front of the piston and causing it to flow through passages I88 and 4'! and tube 46 to the upper end of the actuating cylinder 38. Uncovering the opening 52 by the exhaust port I I8 enables the lower end of the actuating cylinder to vent through the tube 58 and passages 5| and 84 into the reservoir 64. The presser foot is accordingly raised through a distance corresponding to the amount of oil displaced by the metering piston.

After the feed of the work has been completed, openings 88 and 52 are momentarily closed and again uncovered by the exhaust port I88 and the pressure port 88, respectively. Uncovering the openings 88 and 52 by these ports causes a reverse flow of oil through the channels referred to and the presser foot is again actuated to clamp the work. At the same time, the port I82 uncovers the opening I86 in the control valve housing so that the upper end of the actuating cylinder is vented at atmospheric pressure.

The clamping force of the presser foot is maintained on the work as the valve body I8 continues to rotate beyond the left end of the developed surface in Fig. '7 until the ports I84 and 82 at the right end have been reached and passed. A brief period of cut-off is provided between the exhaust ports I82 and I84 and the pressure ports 88 and 82 which looks the presser foot in fixed position and prevents release of the work or change in pressure exerted on the work. During the portion of rotation which provides this cut-off peri0d,the

machine may be brought to rest, so that the bypass valve may be brought into operation effectively to raise or lower the presser foot in stopping or starting the machine.

As in the machine of Patent No. 1,233,539, the

driving and stopping mechanisms are provided with a lever corresponding to that indicated at I28 which is actuated in one direction as the sewing shafts are brought to rest and in the other direction when the operation of the machine is started. In the illustrated machine, the lever I28 is connected through an adjustable link I22 to an arm I24 secured to a central boss on the bypass valve body projecting through a bearing in the base 48. When the machine is brought to rest, the by-pass valve is rocked in the direction of the stop arrow in Fig. 7 and when the machine begins its operations, the valve is rocked in the direction of the start arrow.

The by-pass valve body II, in addition to the central groove I2, is provided with exhaust ports I26 and I28 having radial passages extending into a central cavity I38 of the body (see Fig. 5). The left end of the central cavity is closed by a plate I32 having an exhaust tube I34 leading into the reservoir 64. Pressure ports I38 and I38 are also provided in the valve body connecting with the central groove .12. When the machine is stopped, the pressure port I88 is moved into registry with a double opening I48 in the valve base 48, which opening is connected with the passage 41. At the same time, the port I38 uncovers the opening I48, the exhaust port I26 uncovers a double openingI42 connected with the passage 5I in the base 48. Thus, when the machine comes to rest with the openings in the control valve closed and the by-pass valve moves into the position of Fig. 7, pressure will be applied through port I38, opening I48, passage 41, tube 46, to the upper end of the cylinder 38, causing the presser foot to be disengaged and raised from the work. The lower end of the actuating cylinder 38 is vented through tube 58, passage 5!, opening I42 and the exhaust port I28.

When the machine is started in operation, the ports I38 and I26 move away from the openings I48 and I42 and the ports I28 and I36 uncover these openings momentarily. The positions of the ports I88, I26 and I28, I38 being reversed so From the foregoing description, it is apparent that all of the movements of the presser foot are produced and controlled by hydraulically actuated connections and that no direct mechanical locking devices or actuating mechanisms are relied upon to impart the requisite motions to linkages connected with the presser foot. Neither is it necessary to employ a mechanism having only a portion of its effective stroke utilized either for locking or actuating the presser foot, the remaining portion of the stroke being taken up by yielding or lost motion connections. Consequently, all of the joints between the connections may be made as rigid as practicable according to acceptable machine practices with a View to durability in prolonged use under adverse conditions. The rotary type of control and by-pass valve employed is particularly effective for transferring pressure from one side of the piston to the other while imparting the desired motions to -the presser foot since the cut-off characteristics of valves of this type include a relatively gradual throttling action so as to soften the tendency towards impact in the hydraulic system. The throttling effect of the various ports in these valves as they reach a position out of register with the corresponding openings in the valve housings also reduces any tendency in the linkages connecting the actuating piston with the presser foot to vibrate, to such an extent that diificulty from this cause is insignificant even when operated at high speeds. In these respects, certain features of the present invention and the advantages obtained thereby are similar to those resulting from the use in a sewing machine of a hydraulic presser foot look as disclosed in an application for U. S. Letters Patent of Baker, Serial No. 419,099, filed of even date herewith.

Having thus described the invention, What is claimed is:

1. A shoe sewing machine having, in combination, stitch forming devices, a presser foot, a work support and means for actuating the presser foot relatively to the work support to clamp and release the work comprising a liquid pressure responsive member and means for applying hydraulic pressure to and relieving the pressure from the responsive member during each sewing cycle of the stitch forming devices.

2. A shoe sewing machine having, in combination, stitch forming devices, a presser foot, 2. work support, and means for actuating the presser foot relatively to the work Support to clamp and release the work comprising a hydraulic 1h pressure responsive member, a pump for providing a continuous source of liquid under pressure, and a valve actuated during each sewing cycle to control passage of liquid from the pump to th pressure responsive member.

3. A shoe sewing machine having, in combination, stitch forming devices, a presser foot, a work support, and means for actuating the presser foot relatively to the work support to. clamp and release the work comprising a hydraulic pressure responsive member, a" pump for provid-- ing a continuous source of fluid under pressure,

a valve actuated during each sewing cycle to control passage of fluid from the pump to the pressure responsive member, and a pressure storage chamber between the pump and the valve to supply fluid in greater volume than provided by the pump when the, valve is opened.

4. A shoe sewing machine having, in combination, stitch forming devices, a presser foot, a,

work support, and means for actuating the press er foot relatively to the work support to clamp and release the work comprising a hydraulic pressure responsive member, a pump for providing a continuous source of fluid under pressure, anld a valve for controlling passage of fluid from the pump to both sides of the pressure responsive member to cause the presser foot to be forced against the work and to be raised a substantial distance above the surface of the work during each sewing. cycle.

5. A shoe sewing machine having, in combination, stitch forming devices, a sewing shaft for actuating the stitch forming devices, a presser foot, a work support, and means for actuating the presser foot relatively to the work support to clamp and release the work comprising a hydraulic pressure responsive member connected to the presser foot, a source of fluid under pressure, and a valve driven by the sewing shaft connecting LEO the source of fluid with the pressure responsive member. I

6. A shoe sewing machine having, in combination, stitch forming devices, a sewing shaft for actuating the stitch forming devices, a presser foot, a work support, and means for actuating the presser foot relatively to the work support to clamp and release the work comprising a hydraulic pressure responsive member connected to the presser foot, a source of fluid under pressure, a valve driven by the sewing shaft connecting the source of fluid with the pressure responsive memher, and a metering device connected between the fluid source and the pressure responsive member to limit the movement of the presser foot by said pressure responsive member.

'7. A shoe sewing machine having, in combination, stitch formingdevic'es, a' sewing shaft for actuating the stitch forming devices, a presser foot, a work support, and means for actuating the presser foot relatively to the work support to clamp and release the work comprising a hydraulic pressure responsive member connected to the presser foot, a source of fluid'under pressure, a valve driven'by the sewing shaft con-' necting the source of fluid with the pressure responsive member; a metering cylinder connected between the fluid source and the pressure responsive member, a piston in the metering cylinder, and an adjustable stop for restricting the piston in the cylinder to limit the movement of the presser foot by said pressure responsive member.

8. A shoe sewing machine having, in combination, stitch forming devices, a sewing shaft for actuating the stitch forming devices, a presser foot,.a work support, and means for actuating the presser foot relatively to the work support to clamp and releasethe work-comprising a hydraulic pressure responsive member connected to the presser foot, a valve driven by said sewing shaft connecting the source of fluid with the pressure responsive member, a metering cylinder connected between the fluid source and the pressure responsive member, a' flow blocking piston in the metering cylinder, a stop for restricting the piston in the cylinder to limit the presser foot lifting movement-imparted to said pressure responsive member, and a port in the valve for admitting fluid under pressure to the pressure'responsive member to raisethe presser foot from the work.

9. A shoe sewing machine having, in combination, stitch forming devices, a sewing shaft for actuating the stitch forming devices, a presser foot, a work support, and-means for actuating the presser foot relatively to the'worksupport to clamp. and releasethe work comprising -a hy-' draulic pressure responsive member connected tothe presser foot, a valve driven by said'sewing shaft connecting the source of fluid with the pressure responsive member, a metering cylinder connected between the fluid source and the pressure responsive member, a flow blocking piston in the metering cylinder, a stop for restricting the piston in the cylinder to limit the movement of the presser foot imparted by the pressure responsive member, and ports in the valve for exhausting the fluid from the pressure responsive member and the metering cylinder.

10. A shoe sewing machine having, in combination, stitch forming devices, a sewing shaft for actuating the stitch forming devices, a presser foot, a work support, and means for actuating the presser foot relatively to the work support to clamp and release the work comprising a hydraulic pressure responsive member connected to the presser foot, a valve driven by said sewing shaft connecting the source of fluid with the pressure responsive member, a metering cylinder connected between the fluid source and the pressure responsive member, a flow blocking piston in the metering cylinder, a stop for restricting the piston in th cylinder to limit the movement of the presser foot imparted by the pressure responsive member, a first port in the valve for exhausting the fluid from one side of the pressure responsive member to enable the presser foot to clamp the work, and a second port in the valve for exhausting the pressure from one end of the metering cylinder while the presser foot is clamping the work.

11. A shoe sewing machine having, in combination, stitch forming devices, a sewing shaft for actuating the stitch forming devices, a presser foot, a work support, and means for actuating the presser foot relatively to the work support to clamp and release the work comprising a hydraulic pressure responsive member connected to the presser foot, a valve driven by said sewing shaft connecting the source of fluid with the pressure responsive member, a metering cylinder connected between the fluid source and the pressure responsive member, a flow blocking piston in the metering cylinder, a stop for restricting the piston in the cylinder to limit the movement of the presser foot imparted by the pressure responsive member, a first port in the valve for exhausting the fluid from one side of the pressure responsive member to enable the presser foot to clamp the work, a second port in the valve for exhausting the pressure from one end of th metering cylinder while the presser foot is clamping the work, and a third port in the valve for exhausting the other side of the pressure responsive member only, to cause the presser foot to be raised a distance from the surface of the work determined by the volume of fluid displaced in the metering cylinder.

12. A shoe sewing machine having, in combination, stitch forming devices, a sewing shaft for actuating the stitch forming devices, a presser foot and a work support for clamping and releasing the work during each sewing cycle, driving and stopping mechanisms for bringing the sewing shaft to rest with the stitch forming devices in predetermined relative positions, a hydraulic pressure responsive member connected to the presser foot, a source of fluid under pressure, a control valve driven by the sewing shaft for connecting the source of fluid with the pressure responsive member to cause the presser foot to clamp the work, and a by-pass valve actuated by the driving and stopping mechanisms for relieving the work clamping pressure on the responsive member whenever the sewing shaft is brought to rest. 7 g

13. A shoe sewing machine having, in combination, stitch forming devices, a sewing shaft for actuatingthe stitch forming devices, a presser foot anda work support for clamping and releasing the work during each sewing cycle, driving and stopping mechanisms for bringing the sewing shaft to rest with the stitch forming devices in predetermined relative positions, a hydraulic pressure responsive member connected to the presser foot, a source of fluid under pressure, a control valve driven by the sewing shaft for connecting the source of fluid with the pressure responsive member to cause the presser foot to clamp and release the Work, a by-pass valve actuated by the driving and stopping mechanisms having a port to relieve the work clamping pressure on the responsive member, and another port for admitting fluid under pressure to the responsive member to raise the presser foot from the work at the end of a seam.

' 14. A shoe sewing machine having, in combination, stitch forming devices, a sewing shaft for actuating the stitch forming devices, a presser foot and a work support for clamping and releasing the work during each sewing cycle, driving and stopping mechanisms for bringing the sewing shaft to rest with the stitch forming devices in predetermined relative positions, a hydraulic pressure responsive member connected to the presser foot, a source of fluid under pressure, a control valve driven by the sewing shaft for connecting the source of fluid with the pressure responsive member to cause the presser foot to clamp and release the work, a by-pass valve actuated by the driving and stopping mechanisms having a port to relieve the work clamping pressure on the responsive member, and another port for admitting fluid under pressure to the responsive member to raise the presser foot from the work at the end of a seam, and additional ports for causing the presser foot to again clamp the work as the machine is started in operation.

15. A shoe sewing machine having, in combination, stitch forming devices, a sewing shaft for actuating the stitch forming devices, a presser foot, a work support and mechanism for actuating the presser foot relatively to the work support comprising a hydraulic pressure member connected to the presser foot, a rotary valve connected to fluid confining spaces at the ends of the pressure member, a gear connected to the valve, and means driven continuously from the sewing shaft for rotating the gear to lock the presser foot in fixed position during a portion ofeach sewing cycle.

- OTTO R. HAAS. 

